1. Field of the Invention
The present invention refers in general to the field of mobile telephones and in particular to a mobile telephone network. More in particular, the present invention refers to a method and a system for simulating the behaviour of a mobile telephone network, that can provide services through shared-access channels, based for example on the GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) standard or on the EDGE (Enhanced Data for GSM Evolution) standard or on the HSDPA (High-Speed Downlink Packet Access) standard or on the UMTS (Universal Mobile Telecommunication System) standard.
2. Description of the Related Art
Planning of a network requires the designers to evaluate performances of a network based on geographic data, on network configurations and on expected service requests. The tools that simulate the operation of a network provide a practical method for planning the network itself. The network planning tools allow the designers to simulate the operation of various network configurations by performing modifications on the network based on statistical data obtained as simulation output.
Currently-available cellular network planning tools are generally based on simulators of the static type or of the dynamic type.
In static simulations, the time variable is not taken into account, but the network is analysed in a particular state, as if it were analysed through a photograph. By carrying out many network analyses (many “photographs” called “snapshots”) in different states, it is possible to obtain a global network evaluation.
A static simulation of a GSM network is described, for example, in T. M. Gill “A simulation of a GSM network with frequency hopping”, 1991 Sixth International Conference on Mobile Radio and Personal Communications (Conf. Pul. No. 351) p. 167-74.
In dynamic simulations, the time variable is instead taken into account and the subsequent changes of the network state are regulated by “events”; each “event” represents the realisation of a condition that determines the change of the network state. By carrying out a simulation that takes into account the network state evolution for a certain time length, it is possible to obtain a global network evaluation.
In WO 02/104055, in the name of the Applicant itself, a dynamic simulation system is for example disclosed, characterised by a modular structure based on interchangeable objects that are able to be selectively activated, which comprises a simulation engine and a plurality of modules representative of apparatuses and elements of the network to be simulated. Due to such structure, the system allows simulating highly complex networks.
Dynamic simulators are also used for simulating the mobile telephone networks with shared-access channels (such as for example the GPRS network). The shared-access channels are physical channels, generally used for packet data transmission, which can be shared among many users. For example, the shared-access channels can be used when the packet data transmission is of the intermittent type (such as the download of a Web page) or when a mobile terminal uses a service of the Best-Effort type, namely a service for which the mobile telephone operator cannot guarantee a high quality level. Suitable algorithms, so-called scheduling algorithms, which are part of the set of procedures/algorithms for managing radio resources (Radio Resource Management or RRM) in a mobile telephone network, schedule, in time, the sharing of a single physical channel among different users.
Dynamic simulators, taking into account the time variable, are able to simulate the behaviour of the mobile telephone networks with shared-access channels. In particular, the use of dynamic simulators allows evaluating the effect/impact of scheduling algorithms on performances of this type of networks.